CVE-2021-27852
Checkbox Survey Deserialization of Untrusted Data Vulnerability
- Critical 9.8
- Exploited: added to CISA KEV 11 Apr 2022
Description
Deserialization of Untrusted Data vulnerability in CheckboxWeb.dll of Checkbox Survey allows an unauthenticated remote attacker to execute arbitrary code. This issue affects: Checkbox Survey versions prior to 7.
Key facts
- Published
- 27 May 2021
- Last changed
- 21 Oct 2025
- Assigned by
- certcc
- KEV added
- 11 Apr 2022
- KEV fix due
- 2 May 2022
- EPSS
- 30.258% likely to be exploited in the next 30 days, higher than 98.252% of CVEs (scores for 15 Nov 2026)
- SSVC (CISA)
- Exploitation: active; Automatable: yes; Technical impact: total
Severity scores
Each score is shown as its source gave it. They are not averaged or merged.
- 9.8CVSS 3.1, Criticalfrom the CNA (certcc)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
What to do
- Versions 6 and earlier for this product are end-of-life and must be removed from agency networks. Versions 7 and later are not considered vulnerable.CISA KEV required action
Historical context and remediation
This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.
No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.
Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.
Affected products
| Vendor | Product | Versions |
|---|---|---|
| Checkbox | Survey |
|
Timeline
- 27 May 2021 Published
- 11 Apr 2022 CVE-2021-27852 added to CISA KEV
- 11 Apr 2022 Added to the CISA KEV catalogue